Segments (Results of Operations and Average Assets by Segment) (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Segment Reporting Information
Impairment of Branches and Land	$ 3	$ 20
Bank premises and equipment held for sale	36		$ 27
Right of use asset, operating lease impairment	2	2
Commercial Banking \| Operating lease equipment
Segment Reporting Information
Other Asset Impairment Charges	3	0
General Corporate and Other
Segment Reporting Information
Bank premises and equipment held for sale	$ 36	$ 78

Amount classified as property, plant and equipment attributable to disposal group held for sale or disposed of.

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Amount of loss from impairment of right-of-use asset from operating lease.

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